Blow-down, Twists, Lightning
Blow-down:
With blowdown, the tree is pushed over and damaged by high winds. There is very little you can do to storm proof or protect a tree from hurricanes, down-drafts or tornado winds. The wind force on a tree is often too great for the wood structure. Past tree abuse, poor maintenance and pest problems all predispose the tree to storm damage by weakening the supporting wood.
The "Cure": Keep trees healthy with timely watering and proper fertilization but don't over do. Healthy, vigorous trees adjust more quickly to changes in the environment, are more wind firm and react more effectively to damage. Remove or treat pest problems.
Crown Twist:
Crowns are trees' leaves, twigs and branches. Trees are never perfectly symmetrical in all directions. But many trees, through past abuse and poor management, have lopsided crowns which can cause wind loading. More wind on one side of the crown than on another produces a twist on branches and the main stem. Stem twisting will magnify weaknesses around old injuries and the stem will split or branches collapse.
The "Cure": Eliminate lopsided crowns. Prune branches to produce a reasonably symmetrical crown. If more than 70 percent of the crown is on one side of a mature tree, consider tree removal and replacement. Guying and bracing branches are last-ditch efforts when a tree has to be saved in spite of itself.
Lightning Strike:
Lightning either moves in a narrow line down the branches, stems and roots or along the entire tree bole. Lightning directly destroys tree tissues by electrical disruption and heat all the way down the stem and there can be massive root damage. Damage caused by lightning leads to extensive water loss. Pests quickly attack a lightning weakened and damaged tree.
The "Cure": Install lightning protection systems on historic, rare, specimen or recreational area trees. Unfortunately, lightning strike is fairly common and most trees just can't be protected.
With blowdown, the tree is pushed over and damaged by high winds. There is very little you can do to storm proof or protect a tree from hurricanes, down-drafts or tornado winds. The wind force on a tree is often too great for the wood structure. Past tree abuse, poor maintenance and pest problems all predispose the tree to storm damage by weakening the supporting wood.
The "Cure": Keep trees healthy with timely watering and proper fertilization but don't over do. Healthy, vigorous trees adjust more quickly to changes in the environment, are more wind firm and react more effectively to damage. Remove or treat pest problems.
Crown Twist:
Crowns are trees' leaves, twigs and branches. Trees are never perfectly symmetrical in all directions. But many trees, through past abuse and poor management, have lopsided crowns which can cause wind loading. More wind on one side of the crown than on another produces a twist on branches and the main stem. Stem twisting will magnify weaknesses around old injuries and the stem will split or branches collapse.
The "Cure": Eliminate lopsided crowns. Prune branches to produce a reasonably symmetrical crown. If more than 70 percent of the crown is on one side of a mature tree, consider tree removal and replacement. Guying and bracing branches are last-ditch efforts when a tree has to be saved in spite of itself.
Lightning Strike:
Lightning either moves in a narrow line down the branches, stems and roots or along the entire tree bole. Lightning directly destroys tree tissues by electrical disruption and heat all the way down the stem and there can be massive root damage. Damage caused by lightning leads to extensive water loss. Pests quickly attack a lightning weakened and damaged tree.
The "Cure": Install lightning protection systems on historic, rare, specimen or recreational area trees. Unfortunately, lightning strike is fairly common and most trees just can't be protected.
Stem, Root, Branch Failures
Stem Failure:
Trees do not heal wounds and can only grow over old wounds to seal them off. A tree carries every injury its ever had and the sites of these injuries are structurally weaker than normal solid wood. These weak areas can quickly fail under storm conditions leading to stem damage and breakage.
The "Cure": Properly prune by cutting branches before they become larger than 1 inch in diameter. Do not damage the branch collar as it is part of the stem. Do not over-treat tree hollows by removing decayed wood unless it falls away in your hands. Cleaning hollows can lead to further internal damage. Cover the openings to hollows to allow the tree to grow over the opening. Covering also prevents animals from digging out the hollow and keeps water from running in.
Root Failure:
You need to know that there are two types of tree roots: fine, absorbing roots and woody, structural roots. Both types are important in anchoring a tree. If these roots are constrained, diseased or damaged a tree can lean or fall.
The "Cure": Avoid constraining the root systems by boxing in between foundations, sidewalks and pavement. Construction damage and compaction can kill roots and invite diseases - supervise all construction. Remember, as a tree becomes larger, greater stress is put on the roots. Problems associated with root damage and constraints will show up as the tree ages.
Branch Failure:
A branch is attached to a tree by a small layer of stem wood called the branch collar. Branches are designed to come off at times and a healthy tree will seal off that spot over time. Ice storms or downbursts that occur only rarely will leave the branches unprepared and susceptible to tearing downward along the stem or snapping.
The "Cure": Again, proper pruning minimizes a number of structural problems that occur in association with new wood growth around a pruned branch. Remove or treat pest problems such as branch cankers to minimize potential damage.
Trees do not heal wounds and can only grow over old wounds to seal them off. A tree carries every injury its ever had and the sites of these injuries are structurally weaker than normal solid wood. These weak areas can quickly fail under storm conditions leading to stem damage and breakage.
The "Cure": Properly prune by cutting branches before they become larger than 1 inch in diameter. Do not damage the branch collar as it is part of the stem. Do not over-treat tree hollows by removing decayed wood unless it falls away in your hands. Cleaning hollows can lead to further internal damage. Cover the openings to hollows to allow the tree to grow over the opening. Covering also prevents animals from digging out the hollow and keeps water from running in.
Root Failure:
You need to know that there are two types of tree roots: fine, absorbing roots and woody, structural roots. Both types are important in anchoring a tree. If these roots are constrained, diseased or damaged a tree can lean or fall.
The "Cure": Avoid constraining the root systems by boxing in between foundations, sidewalks and pavement. Construction damage and compaction can kill roots and invite diseases - supervise all construction. Remember, as a tree becomes larger, greater stress is put on the roots. Problems associated with root damage and constraints will show up as the tree ages.
Branch Failure:
A branch is attached to a tree by a small layer of stem wood called the branch collar. Branches are designed to come off at times and a healthy tree will seal off that spot over time. Ice storms or downbursts that occur only rarely will leave the branches unprepared and susceptible to tearing downward along the stem or snapping.
The "Cure": Again, proper pruning minimizes a number of structural problems that occur in association with new wood growth around a pruned branch. Remove or treat pest problems such as branch cankers to minimize potential damage.
